Peptide library / Digestive & weight / PYY 3-36
PYY 3-36
A gut hormone released after eating that reduces hunger, studied for obesity but never approved.
Effects studied or claimed
What it is used or promoted for, and where each effect has actually been seen
- Reduced appetite after infusionSmall human studies
- Weight loss as a drugSmall human studies
How it is thought to work
PYY 3-36 binds the Y2 receptor in the brain's appetite circuits, which reduces food intake for several hours.
What the evidence shows
Infusion studies in the early 2000s showed that giving PYY 3-36 lowered meal size. A nasal spray version did not produce meaningful weight loss and development stopped.
Safety and unknowns
Nausea was dose limiting in infusion studies.
Regulatory status
Not approved. Sold only as a research chemical by unregulated sellers.
Regulatory status changes quickly. This entry was last reviewed on 27 October 2026. Confirm current status with the FDA before relying on it.
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General information, not medical advice. Do not buy or inject unregulated peptides.